Fibers of aligned single-wall carbon nanotubes and process for making the same

ABSTRACT

The present invention involves fibers of highly aligned single-wall carbon nanotubes and a process for making the same. The present invention provides a method for effectively dispersing single-wall carbon nanotubes. The process for dispersing the single-wall carbon nanotubes comprises mixing single-wall carbon nanotubes with 100% sulfuric acid or a superacid, heating and stirring under an inert, oxygen-free environment. The single-wall carbon nanotube/acid mixture is wet spun into a coagulant to form the single-wall carbon nanotube fibers. The fibers are recovered, washed and dried. The single-wall carbon nanotubes were highly aligned in the fibers, as determined by Raman spectroscopy analysis.

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This application claims priority from United States provisionalapplications, Serial No. 60/303,469, entitled “Single Wall CarbonNanotube Alewives” and No. 60/303,470, entitled “Intercalated SingleWall Carbon Nanotube (I-SWNT) Solids As Easily Dispersible Materials,”both filed Jul. 6, 2001, No. 60/337,561, entitled “Carbon Alewives:Intrinsically Aligned Aggregates of Single Wall Carbon Nanotubes” filedNov. 8, 2001, and No. 60/337,951, entitled “SWNT Fibers Spun From SuperAcids,” filed Dec. 7, 2001, which applications are each incorporatedherein by reference.

[0002] This patent application is related to U.S. patent applicationSer. No. ______, “Single-Wall Carbon Nanotube Alewives, Process forMaking, and Compositions Thereof,” to Smalley, et al., (Attorney DocketNo. 11321-P032US), filed concurrent herewith and incorporated herein byreference.

[0003] This invention relates to fibers comprising aligned single-wallcarbon nanotubes and process for making the same.

[0004] This invention was made with United States Government supportunder Grant No. JSC NCC 9-77 awarded by the National Aeronautical andSpace Administration, Grant No. DMR-9802892 awarded by the NationalScience Foundation, and DURINT Grant Nos. N00014-01-1-0789 andN00014-01-1-0791 awarded by the Office of Naval Research. Funding wasalso provided by the Texas Advanced Technology Program Grant No.99-003604-0055-199, and the Robert A. Welch Foundation Grant No. C-0689.Government may have certain rights in the invention.

BACKGROUND OF THE INVENTION

[0005] Single-wall carbon nanotubes (SWNT) are fullerenes of closed-cagecarbon molecules typically arranged in hexagons and pentagons. Commonlyknown as “buckytubes,” these cylindrical carbon structures haveextraordinary properties, including high electrical and thermalconductivity, as well as high strength and stiffness. (See B. I.Yakobson and R. E. Smalley, American Scientist, Vol. 85, July-August,1997, pp. 324-337.)

[0006] With an intrinsic strength estimated to be on the order of 100times-that of steel, single-wall carbon nanotubes are a possiblestrengthening reinforcement in composite materials. The intrinsicelectronic properties of single-wall carbon nanotubes also make themelectrical conductors and useful in applications involving fieldemission devices, such as flat-panel displays, and in polymers used forradiofrequency interference and electromagnetic shielding that requireelectrical conductance properties. In other applications involvingelectrical conduction, single-wall carbon nanotubes and ropes ofsingle-wall carbon nanotubes are useful in electrically conductivecoatings, polymers, paints, solders, fibers, electrical circuitry, andelectronic devices, including batteries, capacitors, transistors, memoryelements, current control elements, switches and electrical connectorsin micro-devices such as integrated circuits and semiconductor chipsused in computers. The nanotubes are also useful as antennas at opticalfrequencies as constituents of non-linear optical devices and as probesfor scanning probe microscopy such as are used in scanning tunnelingmicroscopes (STM) and atomic force microscopes (AFM). Their exceptionalthermal conductivity properties render single-wall carbon nanotubesuseful in composites, coatings, pastes, paints and other materials whereheat transfer is a desired property. In composite materials, alignedsingle-wall carbon nanotubes can provide enhanced electrical,mechanical, optical, and/or thermal properties. Single-wall carbonnanotubes can be used as replacement for, or in conjunction with, carbonblack in tires for motor vehicles, and as elements of compositematerials to elicit specific physical, chemical or mechanical propertiesin those materials, such as electrical and/or thermal conductivity,chemical inertness, mechanical toughness, etc. The nanotubes themselvesand materials and structures comprising carbon nanotubes are also usefulas supports for catalysts in chemical processes, such as hydrogenation,polymerization and cracking, and in devices such as fuel cells.

[0007] To capture the exceptional properties of single-wall carbonnanotubes, numerous attempts have been made to incorporate the nanotubesinto other materials, such as polymers, ceramics, metals and materialsof manufacture. However, one of the problems encountered in makingcomposite blends is the difficulty in dispersing single-wall carbonnanotubes. With a better dispersion of the nanotubes, more of thenanotube properties could be imparted to the composite medium at a lowernanotube loading.

[0008] The largest complication in dispersing single-wall carbonnanotubes is their propensity to tightly self-associate with each other.When single-wall carbon nanotubes come in close contact with each other,they tend to become tightly bound by van der Waals forces, which act tohold the nanotubes tightly together as “ropes” of aligned bundles of afew to many hundreds of nanotubes. Besides this ordered ropingalignment, there is also significant disordered entanglement when manyof the single-wall carbon nanotubes and ropes of single-wall carbonnanotubes contact each other randomly during synthesis, externalcompression and/or subsequent purification. These randomly oriented,entangled mats of individual single-wall carbon nanotubes and ropes ofsingle-wall carbon nanotubes are very difficult to disperse into othermaterials, such as polymers, either as individual single-wall carbonnanotubes or ropes of single-wall carbon nanotubes. The compression andmatting is especially problematic after purification processes involvingliquid-phase treatments, such as described in Chiang, et. al.,“Purification and Characterization of Single-Wall Carbon Nanotubes,” J.Phys. Chem. B, 105, 1157-1161, (2001). In this procedure and other wetmethods, the single-wall carbon nanotubes are wetted with water or someother solvent, either in the chemical purification or as part of thefiltering and washing. Subsequent drying by evaporation causes thesingle-wall carbon nanotubes to more closely associate and remaintightly associated through van der Waals interactions. With evaporationdrying, the bulk density of the single-wall carbon nanotubes increasesmore than an order of magnitude over the initial raw material whose bulkdensity is of the order of 0.01 g/cc. Densification occurs becausecapillary forces promote a collapse of the space between the ropes ofsingle-wall carbon nanotubes that exist in the original sample. A densersingle-wall carbon nanotube product complicates the formation of asubstantially uniform dispersion of single-wall carbon nanotubes inapplications where dispersal of the individual single-wall carbonnanotube segments and ropes is desirable or required. Redispersing theindividual single-wall carbon nanotubes or single-wall carbon nanotuberopes after they are in the denser matted form is difficult andproblematic. Further processing to achieve redispersion may not onlyaffect the nanotube properties, but also increases the cost ofcomposites and final products due to higher labor and equipmentrequirements.

[0009] A related complication in dispersing single-wall carbon nanotubesis that due to their chemical composition and structure, the nanotubesare generally quite insoluble in liquids and other media. The nanotubeswould generally tend to self-associate with each other through van derWaals interactions rather than disperse in other media.

[0010] The ability to disperse single-wall carbon nanotubes remains oneof the largest barriers in realizing the full potential of single-wallcarbon nanotubes in various applications. Besides the challenge ofdispersing single-wall carbon nanotubes, even when dispersed, thesingle-wall carbon nanotubes and ropes of single wall carbon nanotubesmay not provide the optimum configuration to achieve the full potentialof the strength and properties of the nanotubes unless they are aligned.Controlled alignment of single-wall carbon nanotubes fromsurfactant-assisted suspensions and fabrication of macroscopic forms ofsingle-wall carbon nanotubes such as fibers or shear-aligned aggregatesface the inherent limitations of the single-wall carbonnanotube-surfactant system. Since the van der Waals forces between thesingle-wall carbon nanotubes and ropes of single-wall carbon nanotubesare larger than the weak electrostatic repulsions arising from theadsorbed surfactant molecules, the single-wall carbon nanotube solutionsare generally very low in concentration and impractical for manyapplications. Although oriented single-wall carbon nanotube fibers couldbe prepared with surfactant dispersions by shear flow-induced alignmentin a co-flowing stream of polymer solution, the single-wall carbonnanotube concentrations attainable in a sodium dodecyl benzenesulfonate/single-wall carbon nanotube/water system are generally too low(i.e., less than about 1 wt %) to achieve coordinated single-wall carbonnanotube alignment.

[0011] Some methods to disperse single-wall carbon nanotubes havefocused on overcoming the van der Waals forces which hold the nanotubesin intimate contact. One chemical approach to separating the nanotubesand making them more soluble includes functionalization withsolubilizing moieties, either on the ends and/or the sides of thenanotubes. See “Carbon Fibers Formed from Single-Wall Carbon Nanotubes,”International Pat. Publ. WO 98/39250 published Sep. 11, 1998, and“Chemical Derivatization of Single-Wall Carbon Nanotubes to FacilitateSolvation Thereof, and Use of Derivatized Nanotubes,” International Pat.Publ. WO 00/17101, published Mar. 30, 2000, both of which areincorporated by reference herein in their entirety. Another way ofdispersing single-wall carbon nanotubes is by introducing anintercalating species that will separate the nanotubes using aphysio-chemical approach. Oleum, a well-known superacid, has been usedas an intercalating species so as to suspend and disperse single-wallcarbon nanotubes and make large “super ropes” of aligned nanotubes. See“Macroscopic Ordered Assembly of Carbon Nanotubes,” International Pat.Publ. WO 01/30694 A1, published May 3, 2001, incorporated by referenceherein in its entirety. Physical methods for inducing separation of thenanotubes have included sonication and other means of intensive mixing.However, these aggressive techniques can induce damage, shear andbreakage in the nanotubes, and, thereby, compromise the desired nanotubeproperties for the intended application.

[0012] Wrapping single-wall carbon nanotubes with amphiphilic polymershas also been shown as a means to overcome van der Waals forces betweensingle-wall carbon nanotubes. See “Polymer-Wrapped Single Wall CarbonNanotubes,” International Pat. Publ. WO 02/16257 published Feb. 28,2002, incorporated by reference herein in its entirety. Although polymerwrapping of the nanotube enables the dispersion of single-wall carbonnanotubes in water and other solvents, higher concentrations ofnanotubes dispersed in other media over a broad range of temperatureconditions are often desired.

[0013] Thus, there is a need for a form of single-wall carbon nanotubesin which the nanotubes are aligned and can be dispersed in other media,such as polymers, ceramics, metals and other media used in manufacture.There is also a need to be able to redisperse the aligned aggregate intoindividual nanotubes or smaller aggregates of single-wall carbonnanotubes. Likewise, there is a need for composites comprisingdispersed, highly aligned single-wall carbon nanotubes.

SUMMARY OF THE INVENTION

[0014] The present invention is a composition of matter which provides anew discrete aggregate comprising highly-aligned single-wall carbonnanotubes. The aggregates are called “carbon alewives” for theirresemblance to the Atlantic fish bearing that name. The single-wallcarbon nanotube alewife aggregate is a distinct aggregate. The shape isacicular, or “needle-like,” with a thicker middle that tapers toward theends. Alewives are substantially free of tangles of long ropes and canbe easily dispersed and incorporated into other materials, such aspolymers, metals, ceramics, metal oxides and liquids. The invention alsoincludes composites comprising carbon alewives, wherein the single-wallcarbon nanotubes are substantially aligned and impart properties of thesingle-wall carbon nanotubes, such as reinforcement, enhanced tensilestrength and/or electrical and thermal conductivity, to the composite.

[0015] The invention provides a method for preparing carbon alewives.The method comprises introducing single-wall carbon nanotubes into 100%sulfuric acid or a superacid and mixing at room or an elevatedtemperature under an inert, anhydrous and oxygen-free environment. Thecarbon alewives are formed by introducing moisture into the mixture ofsingle-wall carbon nanotubes and anhydrous 100% sulfuric acid orsuperacid at room or an elevated temperature. The alewives arerecovered, washed and dried to form dry carbon alewives. For a given setof preparation conditions, the size of the alewives is dependent on theinitial single-wall carbon nanotube concentration in the acid and ismonodisperse for each concentration, with smaller alewives formed atlower concentrations. The invention provides an aggregate form ofaligned single-wall carbon nanotubes that enables the incorporation ofhighly-aligned single-wall carbon nanotubes into other materials, suchas polymers, metals, ceramics and liquids, over a broad range ofconcentrations with good dispersion of the nanotubes so as to enhancethe properties of the resulting composite material. Because thesingle-wall carbon nanotube alewives are discrete aggregates, they areeasy to handle and process. The invention also enables the formation ofsingle-wall carbon nanotube/polymer masterbatches, where the nanotubeconcentration in the polymer is generally higher than desired for theend-use, so that the masterbatch can be mixed with more polymer inprocessing to achieve the desired concentration for the particularend-use.

[0016] The invention also provides a method for producing “super ropes”and fibers of aligned single-wall carbon nanotubes using anhydrous 100%sulfuric acid or other superacids.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 shows a scanning electron micrograph of single-wall carbonnanotube alewives at 500× magnification obtained from a 4 wt %single-wall carbon nanotube/oleum/water system. FIG. 2 shows a scanningelectron micrograph of single-wall carbon nanotube alewives at 2500×magnification.

[0018]FIG. 3 shows a scanning electron micrograph of single-wall carbonnanotube alewives at 5000× magnification.

[0019]FIG. 4 shows an optical micrograph of single-wall carbon nanotubealewives with a single alewife in the cross-hairs.

[0020]FIG. 5 shows a Raman spectra taken with the Raman laserpolarization vector parallel and perpendicular to the long axis of asingle-wall carbon nanotube alewife.

[0021]FIG. 6 shows a plot of resistivity as a function of temperaturefor raw and annealed fibers extruded from a 6 wt % single-wall carbonnanotube/100% sulfuric acid mixture.

[0022]FIG. 7 shows a plot of thermopower as a function of temperaturefor raw and annealed fibers extruded from a 6 wt % single-wall carbonnanotube/100% sulfuric acid mixture.

[0023]FIG. 8 shows a plot of differential thermopower as a function oftemperature for raw and annealed fibers extruded from a 6 wt %single-wall carbon nanotube/100% sulfuric acid mixture.

DETAILED DESCRIPTION OF THE INVENTION

[0024] The present invention is a composition of matter which provides anew aggregate form comprising of highly-aligned single-wall carbonnanotubes. The aggregates, called “carbon alewives,” have a distinct anddiscrete acicular (needle-like) shape, are substantially free of tanglesof long ropes and can be easily dispersed and incorporated into othermaterials, such as polymers, metals, ceramics and liquids, over a broadrange of concentrations. The invention provides a means of preparingcarbon alewives in which the single-wall carbon nanotubes aresubstantially aligned and retain their tensile and conductiveproperties. This invention also provides a means of preparing fibers ofaligned single-wall carbon nanotubes.

[0025] Carbon alewives are discrete aggregates, the size of which isdependent on the particular preparation conditions. Alewives have acenter thickness that is generally in the range between about 0.5microns and about 10 microns wide, more typically between about 2 andabout 5 microns wide. The length of the carbon alewives is generally upto about 50 microns, typically in the range between about 10 and about50 microns in length, more typically in the range between about 10 andabout 30 microns. The size of the single-wall carbon nanotube alewivescan be dependent on the initial single-wall carbon nanotubeconcentration in 100% sulfuric acid or superacid in which they are made.For a given set of preparation conditions, smaller alewives are observedat lower concentrations. The size of the alewives is generallymonodisperse at any concentration.

[0026] Although carbon alewives are discrete aggregates, anotherembodiment of this invention includes the form of carbon alewives wherethe alewives are connected end-to-end. The carbon alewives are generallystraight, however another embodiment of this invention includes curvedor crescent-shaped alewives.

[0027] Carbon alewives can be made using single-wall carbon nanotubesprepared by any known method. Single-wall carbon nanotubes prepared bythe gas-phase reaction of high pressure carbon monoxide and a transitionmetal catalyst, such as described in “Gas Phase Nucleation and Growth ofSingle-Wall Carbon Nanotubes from High Pressure Carbon Monoxide,”International Pat. Publ. WO 00/26138, published May 11, 2000,incorporated by reference herein in its entirety, are preferred. Thesingle-wall carbon nanotubes can be used as-synthesized or afterpurification. Purification can be performed by any method known by thoseof ordinary skill in the art. For methods of purification, see “Processfor Purifying Single-Wall Carbon Nanotubes and Compositions Thereof,”International PCT Patent Application, Ser. No. PCT/US02/03957, filedFeb. 11, 2002, and “Gas-Phase Process for Purifying Single-Wall CarbonNanotubes and Compositions Thereof,” International PCT PatentApplication, Ser. No. PCT/US02/03952, filed Feb. 11, 2002, both of whichare incorporated by reference in their entirety herein. Without meaningto be limited, one method of purification which can be used includes agas phase oxidation, aqueous hydrochloric acid treatment and waterwashing. The oxidation, which may be done with or without moisturepresent, serves to oxidize and remove amorphous carbon. The oxidationcan also oxidize the residual catalyst metal after breaching any carbonencapsulation. The oxidation is typically done for about 1 to about 3hours at a temperature range of about 175° C. to about 300° C., inambient air or with oxygen, optionally water vapor, and nitrogen or aninert gas. After oxidation, the single-wall carbon nanotubes are treatedwith aqueous hydrochloric acid which reacts with the metal catalyst toform metal halides which are soluble in the acid solution. Finally, thesingle-wall carbon nanotubes are filtered, washed with water andsolvent, and dried. The dried product is a highly tangled mat ofsingle-wall carbon nanotubes.

[0028] The as-prepared or purified single-wall carbon nanotubes can be,optionally, ground to a sub-millimeter size with a mortar and pestle orother grinding means such as a ball mill. Whether or not the nanotubesare ground, the nanotubes are mixed with 100% sulfuric acid or asuperacid. It has been found that the use of oleum and certain othersuperacids can lead to non-redispersibility of the individual nanotubesin the aggregate. For example, it has been observed that with the use ofoleum, higher SO₃ content in the oleum is more likely to cause theindividual nanotubes in the aggregate to be non-redispersible, “anaggregate non-redispersing acid.” An acid in which the individualsingle-wall carbon nanotubes in the aggregate are substantiallyredispersible in the acid (“an aggregate substantially redispersingacid”) is preferred, if substantial redispersibility of the individualsingle-wall carbon nanotubes in the aggregate is desired. An acid inwhich the individual single-wall carbon nanotubes in the aggregate areredispersible in the acid (“an aggregate redispersing acid”) ispreferred, if redispersibility of the individual single-wall carbonnanotubes in the aggregate is desired. It should be noted that there isa distinction between aggregates (i.e., alewives) being dispersible in amedium and the single-wall carbon nanotubes of the aggregate beingdispersible in a superacid. In the former, the alewives disperse in themedium and retain their integrity as alewives. In the later, theaggregate can lose its integrity in the aggregate substantiallyredispersing acid/aggregate redispersing acid such that the single-wallcarbon nanotubes in the aggregate disperse in that acid.

[0029] Superacids useful for making carbon nanotube alewives can be ofvarious types, such as Brønsted superacids, Lewis superacids, andconjugate Brønsted-Lewis superacids. The superacids can be in a melt,liquid or gaseous form. Brønsted superacids are those whose acidityexceeds that of 100% sulfuric acid. Examples of Brønsted superacidsinclude perchloric acid (HClO₄), chlorosulfuric acid (ClSO₃H),fluorosulfuric acid (HSO₃F), chlorosulfonic acid, fluorosulfonic acid,and perfluoroalkanesulfonic acids, such as trifluoromethanesulfonic acid(CF₃SO₃H), also known as triflic acid, and higherperfluoroalkanesulfonic acids, such as C₂F₅SO₃H, C₄F₉SO₃H, C₅F₁₁SO₃H,C₆F₁₃SO₃H, C₈F₁₇SO₃H,

[0030] and α, ω-perfluoroalkanedisulfonic acids. Lewis superacids havebeen defined by Olah, et al. (See “Superacids” John Wiley & Sons, 1985)as those acids stronger than anhydrous aluminum chloride. Lewissuperacids include antimony pentafluoride, arsenic pentafluoride,tantalum pentafluoride and niobium pentafluoride. Antimony pentafluorideand arsenic pentafluoride form stable intercalation compounds withgraphite. Conjugate Brønsted-Lewis superacids include SO₃-containingsulfuric acids, also known as oleums or polysulfuric acids,polyphosphoric acid-oleum mixtures, tetra(hydrogen sulfato)boricacid-sulfuric acid, fluorosulfuric acid-antimony pentafluoride (alsoknown as “magic acid”), fluorosulfuric acid-sulfur trioxide,fluorosulfuric acid-arsenic pentafluoride, HSO₃F:HF:SbF₅,HSO₃F:SbF₅:SO₃, perfluoroalkanesulfonic acid-based systems, such asCnF_(2n+1)SO₃H:SbF₅, where n=1, 2 or 4, and CF₃SO₃H:B(SO₃CF₃)₃,hydrogen-fluoride-antimony pentafluoride (also known as fluoroantimonicacid), hydrogen fluoride-tantalum pentafluoride, hydrogen fluoride-borontrifluoride (also known as tetrafluoroboric acid), and conjugateFriedel-Crafts acids, such as HBr:AlBr₃, and HCl:AlCl₃. For descriptionand clarity, oleum will be used herein as the exemplary superacid;however, it would be recognized by those of ordinary skill in the art toutilize anhydrous 100% sulfuric acid or any other superacid, such asthose listed above.

[0031] Single-wall carbon nanotubes, as-synthesized, purified and/orground, are mixed with oleum and stirred from at least about 3 hours toup to about 3 days at a temperature ranging from about room temperatureto about 150° C., preferably from about 90° C. to 130° C. Thesingle-wall carbon nanotubes are introduced into the oleum so as toproduce a single-wall carbon nanotube/oleum mixture at a concentrationof about 0.01 wt % to about 10 wt % single-wall carbon nanotubes in themoisture-free oleum. Although not meaning to be bound by theory, it isbelieved that during the mixing process, the oleum intercalates betweenindividual single-wall carbon nanotubes and forms single-wall carbonnanotube ropes having widths ranging from about 30 nm to about 40 nm.The intercalation of the oleum is expected to reduce the effects of thevan der Waals forces and permit the single-wall carbon nanotubes toslide against each other and self-align. The intercalation allows thefurther thickening of the ropes by adding more aligned single-wallcarbon nanotubes to form larger aggregates which are on the order ofabout 200 nm to about 400 nm in diameter. The ropes thicken further to athickness from about 1 to about 2 microns (about 1000 to about 2000 nm).

[0032] The distinct, discrete and unique alewife aggregates are thenformed by slowly adding water to the heated anhydrous single-wall carbonnanotube/oleum mixture. One method of slowly incorporating water is byallowing the anhydrous single-wall carbon nanotube/oleum mixture toabsorb moisture ambient air overnight while heating at a temperaturebetween about 90° C. and 100° C., with optional stirring. The slowincorporation of moisture into the single-wall carbon nanotube/oleumsystem results in a single-wall carbon nanotube/oleum/water mixture andthe formation of carbon alewives. The alewives are isolated from thenanotube/oleum water mixture by dumping the mixture in a suitablesolvent, such as dry ether, and filtering the alewives. The alewives canbe washed with a suitable solvent or solvents, such as methanol, anddried.

[0033] Humidified air or another gas, such as nitrogen or an inert gas,containing water vapor may also be used to introduce water to thesingle-wall carbon nanotube/oleum mixture by passing it over thenanotube/acid mixture. A dry gas may be humidified by passing the gasthrough a water bubbler. The amount of water carried by the gas can becontrolled by the flow rate of the gas and the temperature of the waterin the bubbler. The rate of moisture addition to the single-wall carbonnanotube/acid mixture can be adjusted through control of the amount ofmoisture in the gas in the bubbler and by mixing the moisture-containinggas with a stream of dry gas. By adjusting different parameters,including the temperature of the nanotube/acid mixture and the amount ofstirring, the rate of moisture addition to the nanotube/acid mixture canbe controlled at a low rate so that alewives form from the mixture.Generally, it is desirable to introduce moisture at a slower rate forlower initial single-wall carbon nanotube concentrations in thenanotube/acid mixture.

[0034] A typical scenario for the addition of moisture to ananotube/acid mixture is included in the following procedure using 100%sulfuric acid. A mixture of 4 wt % single-wall carbon nanotubes in 100%sulfuric acid was heated to 110° C. and stirred under flowing argon at50 cc/min for 24 hours. The stirred mixture was exposed to argon thatwas flowing at 50 cc/min through a bubbler containing water at roomtemperature. The temperature of the mixture was lowered to. 70° C. andthe moisture exposure was continued for 6 hours. After moistureexposure, the mixture was dumped into dry diethyl ether. The carbonalewives were washed in diethyl ether and dried overnight at roomtemperature under vacuum. There are many different configurations thatcould be used by those of ordinary skill in the art to control theintroduction of moisture into a nanotube/acid system such that alewivesform.

[0035] Carbon alewives are formed under certain controlled conditions.If water is not added to the anhydrous the single-wall carbonnanotube/oleum mixture, or if water is not added sufficiently slowly, orif the mixture is not heated at a sufficient temperature, the resultingsingle-wall carbon nanotube structure is in a form called “super ropes,”which are approximately one-half micron to about two microns wide. Likesingle-wall carbon nanotubes and single-wall carbon nanotube ropes, thesuper ropes are long, tangled and enmeshed. Recovered and dried superropes would be very difficult to process and disperse in othermaterials.

[0036] Without forming alewives, it is possible to produce fibers ofaligned single-wall carbon nanotube from a nanotube/acid mixture.Generally, it is desirable to extrude fibers with higher concentrationsof single-wall carbon nanotubes in 100% sulfuric acid or a superacid.Superacids, such as those listed above for the preparation of alewivescan be used. Preferred acids are 100% sulfuric acid,trifluromethanesulfonic acid (also known as triflic acid) and oleum.More preferred are 100% sulfuric acid and trifluromethanesulfonic acid.The fibers are made by mixing single-wall carbon nanotubes,as-synthesized, purified and/or ground, with 100% sulfuric acid or asuperacid and stirring from at least about 3 hours to up to about 3 daysat a temperature ranging from about room temperature to about 150° C.,preferably from about 90° C. to 130° C. The nanotube/acid mixture iskept anhydrous and oxygen-free by doing the mixing under nitrogen or aninert gas atmosphere. The single-wall carbon nanotube concentration inthe acid can be in a range of about 0.01 wt % to about 10 wt % orhigher. During the mixing process, it is believed that the components ofthe acid intercalate between individual single-wall carbon nanotubes andpermits the single-wall carbon nanotubes to slide against each other andself-align. The nanotube/acid mixture is extruded through a die, whichalso promotes alignment of the nanotubes, directly into a coagulantwithout contacting a gaseous environment. This type of fiber spinning isgenerally known as wet spinning. Coagulant baths can include water,diethyl ether, ethylene glycol, 10% sulfuric acid, and mixtures thereof.After the fiber is coagulated, it can be washed to remove intercalatingspecies and dried. Suitable washing media can include water, diethylether, methanol and mixtures thereof. Drying means can include airdrying or drying in a heated oven. Drying can also include vacuumdrying. Optionally, the fiber can be post-treated. Not meaning to belimited, post-treatments can include annealing in an inert gas at anelevated temperature and reducing in a hydrogen atmosphere. Annealingtemperatures can be in the temperature range of about 400° C. and 800°C. Temperatures for subjecting the fibers to a reducing environment canbe up to about 450° C. Tension may be applied to the fiber as part ofany post-treatment.

[0037] Carbon alewives, however, are discrete aggregates of highlyaligned single-wall carbon nanotubes. They are generally monodisperse insize and shape for a particular concentration. Recovered and driedalewives of the present invention are shown in scanning electronmicrographs at magnifications of 500×, 2500× and 5000×, in FIGS. 1, 2and 3, respectively.

[0038] For any given preparation conditions, the length and width of thecarbon alewives appears to be dependent on the initial concentration ofthe single-wall carbon nanotubes in acid. For example, the alewivescollected from a 4 wt % single-wall carbon nanotube/oleum/water systemwere about 1 to about 2 microns thick at the center and about 10 toabout 15 microns long. At lower concentrations of single-wall carbonnanotubes, the alewives were thinner and shorter. For example, thealewives collected from a 0.25 wt % and 1 wt % single-wall carbonnanotube/oleum/water systems were up to about a half micron thick at thecenter and about 12 microns long.

[0039] In contrast to the randomness observed in as-synthesized and/orpurified single-wall carbon nanotubes and single-wall carbon nanotuberopes, the single-wall carbon nanotubes in the alewives are highlyaligned. The internal alignment of the single-wall carbon nanotubes inthe alewives was quantified by Raman spectroscopy using the Fraserfraction, f where f=(R−1)/(R+4), and R, the alignment ratio, is theRaman intensity ratio between the parallel and perpendicularorientations of the nanotube aggregates. The value for f can range from0 for an isotropic, random non-alignment to 1 for perfect alignment.Spectra were collected with a Renishaw polarized Raman microanalyzeroperated in the reflectance mode using a linearly polarized laser beamfrom a 780-nm diode laser (2.3 mW, 1 μm beam diameter) as the excitationsource. The ratio of the parallel and perpendicular intensities of theE2g mode at 1593 cm⁻¹ was taken to quantify the single-wall carbonnanotube alignment. Raman spectra were recorded at two differentaggregate orientations, i.e., in the plane of polarization, parallel andperpendicular to the longer axis of each alewife. To perform theanalysis, the orientation of each aggregate is aligned with an opticalmicroscope on a rotating X-Y stage such that the long axis of thealewife is parallel to the plane of polarization of the incident lightbeam before recording a Raman spectrum. FIG. 4 shows an opticalmicrograph of single-wall carbon nanotube alewives with the centeralewife aligned in the cross hairs in order to take the Raman spectra.Raman spectra are then recorded at four different positions along thelength of the aggregate. The sample is then rotated to position theaggregate perpendicular to the plane of polarization. Again, Ramanspectra are recorded at four positions along the length. Measurementsare taken on at least four different alewives and averaged.

[0040]FIG. 5 shows typical Raman spectra of an alewife aggregaterecorded at the parallel and perpendicular modes. The ratio of theaverage intensity of the peak at 1593 cm⁻¹ between the parallel andperpendicular modes was separately calculated for each aggregate. Theinternal alignment of single-wall carbon nanotubes within alewives,obtained from a 4 wt % single-wall carbon nanotube/oleum/water mixture,was examined. The average alignment ratio, Rave, obtained by averagingthe ratios for four different aggregates, was found to be 14.9±1.78 σ(stnd. dev.) A Fraser fraction f value of 0.73 was obtained, indicatinga high degree of internal alignment of the single-wall carbon nanotubesin the alewives. A Fraser fraction f value of at least about 0.25 ispreferred for aligned nanotubes. A Fraser fraction of at least about 0.5is more preferred. A Fraser fraction of at least about 0.7 is mostpreferred.

[0041] The internal alignment of the single-wall carbon nanotubes occursspontaneously even at high nanotube concentrations only in strong,moisture-free, protonating environments such as 100% sulfuric acid andsuperacids. Neither alewives nor super ropes are formed using in 98%sulfuric acid.

[0042] However, single-wall carbon nanotubes can be intercalated withvarious chemicals so as to promote dispersion of the nanotubes.Intercalating species include chemicals such as concentrated nitricacid, concentrated sulfuric acid, 100% sulfuric acid, oleum, mixtures ofpolyphosphoric acid and oleum, fluorosulfuric acid, chlorosulfuric acid,and sulfonic acids (fluorosulfonic, chlorosulfonic, alkyl and aromaticsulfonic and perchloro and perfluoro alkyl and aromatic sulfonic acids),molten metal halides, hydrogen fluoride and the elemental halogens(chlorine, fluorine, bromine and iodine), mixtures of metal halides withhydrogen fluoride and mixtures of elemental halogens with hydrogenfluoride.

[0043] If no redispersing of the nanotubes is desired, the preferredintercalating species is one that does not redisperse the individualnanotubes, “an aggregate non-redispersing species” or, alternatively foracids, “an aggregate non-redispersing acid.” If substantialredispersibility of the single-wall carbon nanotubes is desired, thepreferred intercalating species is one that substantially redispersesthe nanotubes, “an aggregate substantially redispersing species” or,alternatively for acids, “an aggregate substantially redispersing acid.”If redispersion of the nanotubes is desired, the preferred intercalatingspecies is one that redisperses the individual nanotubes, “an aggregateredispersing species” or, alternatively for acids, “an aggregateredispersing acid.”

[0044] In other words, if alewives are desired that will not redispersein an acid to individual single-wall carbon nanotubes, an aggregatenon-redispersing acid can be used. If alewives or super ropes aredesired that will substantially redisperse in an acid to individualsingle-wall carbon nanotubes, an aggregate substantially redispersingacid can be used. And, if alewives or super ropes are desired that willredisperse in an acid to individual single-wall carbon nanotubes, anaggregate redispersing acid can be used.

[0045] Intercalated single-wall carbon nanotubes promote the dispersionof single-wall carbon nanotubes and are a starting material fordispersing the nanotubes in liquids, polymeric materials, ceramics andother solids. Single-wall carbon nanotubes that are intercalated withsulfuric acid readily disperse in water that contains small amount of asurfactant. The rapid dispersion of sulfuric acid-intercalatedsingle-wall carbon nanotubes can occur in other liquids, such asdimethyl formamide, chloroform, and dichlorobenzene. The single-wallcarbon nanotubes may be intercalated by soaking the nanotubes in neatintercalating liquids or exposing single-wall carbon nanotubes togaseous intercalating species, with or without heating. Besidesenhancing dispersion, intercalation of certain chemical species providesa means for preparing single-wall carbon nanotube alewives, super ropesand fibers. The super ropes of single-wall carbon nanotubes have adiameter of about one-half micron to about 2 microns.

[0046] Although not meant to be bound by theory, in the presence of 100%sulfuric acid or superacid, the acid species intercalate the individualnanotubes and nanotube bundles. In the case of oleum, for example, thenanotubes are intercalated with H₂SO₄ and HSO₃ ⁻ ions, and are expectedto carry a positive charge from protonation. With a positive charge onthe intercalated individual single-wall carbon nanotubes or nanotubebundles, the intercalated species induce Coulombic repulsive forceswhich are stronger than the attractive van der Waals forces, so as topermit the individual tubes and bundles to slide past each other andform locally ordered liquid crystal-like domains. When the water isslowly introduced, controlled hydrolysis is followed by slow aggregationof the nanotubes into monodisperse alewives. These aggregates, onceformed, are morphologically stable to thermal annealing under inertatmosphere and reduction in a hydrogen atmosphere.

[0047] Alewives and fibers of highly aligned single-wall carbonnanotubes of this invention provide a fundamental improvement inproducts and articles of manufacture that rely on dispersed, alignedsingle-wall carbon nanotubes. Some of the articles of manufactureinclude, but are not limited to, composite materials with electrical,mechanical, electromagnetic or chemical properties derived in part fromthe single-wall carbon nanotubes contained therein. The dispersion ofaligned single-wall carbon nanotubes in the form of alewives provided bythis invention can enable better properties for applications such aselectromagnetic interference (EMI) and radiofrequency interference (RFI)shielding. Other articles of manufacture include electrodes of fuelcells, capacitors or batteries, particularly lithium-ion batteries;catalyst supports, structure-modifying additives for vehicle tires andlaminated composites, including high-strength carbon fiber composites,anti-corrosion and other electrochemical materials and coatings; fiberscontaining or comprised entirely of single-wall carbon nanotubes,chemical, physical, and electronic sensors; films and coatings; inks andconducting materials that may be printed in any way; electrically andthermally conductive coatings, electrically and thermally conductivecomposite materials, electromagnetic and radiofrequency shieldingmaterials; field emission cathodes; biologically-compatible coatings,objects and devices that are inserted or implanted into livingorganisms; radar-absorbing materials, optically-active materials anddevices; components of systems that convert sunlight to electricalenergy; electronic devices including transistors, pass elements,capacitors, inductors, resistors, connectors, switches, wires,interconnections devices and antennae at frequencies up to and includingoptical frequencies; electronic circuit fabrication materials;electrical and thermal conducting materials, transducers, electricaltransmission cable, high-strength fiber, and structural elements ofmachines, buildings, vehicles, and airframes, components for aircraft,components for missiles, vehicle bodies, bullet-proof vests, armor, andship hulls. Other articles of manufacture improved by the incorporationof single-wall carbon nanotube alewives and fibers include skis,surfboards, sails, racquets, other sporting goods, and woven material,woven with other single-wall carbon nanotube fibers, natural fibers orsynthetic fibers.

[0048] The fundamental improvements enabled by single-wall carbonnanotubes in the foregoing applications are due to the ability toprovide aligned single-wall carbon nanotubes that can be easily handledand dispersed as alewives in the host material. This enhanceddispersion, can permit use of lower loadings of single-wall carbonnanotubes in some applications, so as to retain the desirable propertiesof the host material, while simultaneously providing enhancedelectrical, thermal or tensile properties of the single-wall carbonnanotubes for the particular applications. Improvements in theapplications using fibers of single-wall carbon nanotubes are improvedby the coordinated alignment of the single-wall carbon nanotubes intoimpart strength and provide for higher strength materials.

[0049] The following examples are included to demonstrate preferredembodiments of the invention. It should be appreciated by those of skillin the art that the techniques disclosed in the examples which followrepresent techniques discovered by the inventor to function well in thepractice of the invention, and thus can be considered to constitutepreferred modes for its practice. However, those of skill in the artshould, in light of the present disclosure, appreciate that many changescan be made in the specific embodiments which are disclosed and stillobtain a like or similar result without departing from the spirit andscope of the invention.

EXAMPLES Example 1

[0050] This example demonstrates the preparation and grinding ofpurified single-wall carbon nanotubes.

[0051] Single-wall carbon nanotubes (HiPco™ single-wall carbon nanotubesobtained from Carbon Nanotechnologies, Inc., Houston, Tex.) werepurified to remove residual iron metal catalyst particles and amorphouscarbonaceous impurities. The purification included a gas-phase oxidationand an aqueous hydrochloric acid treatment. After a hydrochloric acidtreatment, the nanotubes were filtered in a Buchner funnel and washedwith a continuous and slow stream of deionized water until the filtratewas neutral. After water washing, the purified single-wall carbonnanotubes were washed repeatedly with methanol, filtered and dried in arotary evaporator.

[0052] Thermogravimetric analysis (TGA) of the dried, purifiedsingle-wall carbon nanotubes in air indicated that the remaining ironimpurity was less than 0.8 atom %. The dried single-wall carbonnanotubes were ground manually with a mortar and pestle until uniform tosub-millimeter level to form a single-wall carbon nanotube powder.

Example 2

[0053] This example demonstrates the preparation of a single-wall carbonnanotube/oleum mixture.

[0054] Using ground single-wall carbon nanotube powder, as prepared inExample 1, a mixture of 4 wt % single-wall carbon nanotubes in oleum(H₂SO₄:20% SO₃) was prepared by mixing using a sealed propeller mixer at130° C. for 12 hours under an inert argon atmosphere.

[0055] No distinct single-wall carbon nanotube alewife aggregates wereobserved in the 4 wt % single-wall carbon nanotube/oleum mixture. Thesingle-wall carbon nanotube formations consisted of thicker, non-uniformropes of single-wall carbon nanotubes, approximately 200 to 400 nm inthickness and randomly entangled as a mat.

Example 3

[0056] This example demonstrates that single-wall carbon nanotubealewives are not formed in an anhydrous system, such as dry ether.

[0057] 0.5 cc of the 4 wt % single-wall carbon nanotube/oleum mixture,prepared in Example 2, was put into about 200 mls of dry ether, followedby stirring and sonication. The resulting single-wall carbonnanotube/dry ether suspension was filtered through a 0.2 micron PTFEfilter. The single-wall carbon nanotubes recovered from the filterformed a bucky paper which was peeled off and vacuum dried. No carbonalewives were observed using the procedures of this example.

Example 4

[0058] This example demonstrates the preparation of single-wall carbonnanotube alewives.

[0059] Moisture was introduced to the 4 wt % single-wall carbonnanotube/oleum mixture, prepared in Example 2, by stirring overnight at90° C. in an atmosphere of ambient air. The resulting single-wall carbonnanotube/oleum/water mixture was then transferred to a glass syringe.About 5 cc of this mixture was injected into about 200 mls of dry etherin a conical flask. The ether suspension was sonicated in a bathsonicator and filtered through a PTFE filter. The remaining solid waswashed with methanol, vacuum dried at room temperature, and collected asa powder. A scanning electron micrograph showed the formation ofalewives. With sonication, the alewives are readily dispersible asindividual aggregates in surfactant-assisted suspensions. A typicalsurfactant that can be used to disperse the aggregates is sodium dodecylbenzene sulfonate. Other surfactants that can be used include sodiumdodecyl sulfate and Triton X-100™. (Triton X-100 was a registeredtrademark formerly owned by Rohm and Haas Co., but now owned by UnionCarbide.)

[0060] The thermal stability of the carbon alewives was tested by TGAunder argon flowing at 100 cc/min. A sample of alewives was heated at arate of 20° C./min under vacuum to 800° C. and held isothermally for onehour. The evolved gases were analyzed by infrared (IR) andmass-spectrometry (MS) and revealed the evolution of primarily SO₃ attemperatures less than 200° C., primarily SO₂, with a small amount ofCO₂, in the temperature range of about 200° C. to about 450° C., andprimarily CO₂ and water above 450° C. Approximately 13% of the totalweight loss in the alewives could be attributed to sulfur-containingspecies.

Example 5

[0061] This example demonstrates the preparation of carbon alewives froma 4 wt % single-wall carbon nanotube/oleum/water mixture.

[0062] A sample of the 4 wt % single-wall carbon nanotube/oleum/watermixture, prepared according to Example 4 but before drying, was taken byglass syringe and introduced dropwise into the ether layer of a diethylether/water bilayer in a 100-ml glass beaker. A thin film of single-wallcarbon nanotube/oleum/water mixture formed immediately and floated atthe ether/water interface. The film was collected on a stub of flataluminum by carefully lowering the stub through the interface and slowlyraising it from beneath the single-wall carbon nanotube/oleum/waterfilm.

[0063] Carbon alewives were collected at the ether/water interface onthe aluminum stub and were approximately 10-15 microns long and 1-2microns thick, as determined by scanning electron microscopy. Ramanspectroscopy showed high internal nanotube alignment within the distinctaggregates.

Example 6

[0064] This example demonstrates the preparation of carbon alewives froma 0.25 wt % single-wall carbon nanotube/oleum/water mixture.

[0065] The same experiments of Examples 4 and 5 were done except thatthe starting material was a 0.25 wt % single-wall carbonnanotube/oleum/water mixture. The alewives were approximately 12 micronslong and up to about a half micron wide and had a similar shape as thoseformed from the 4 wt % single-wall carbon nanotube/oleum/water mixture.

Example 7

[0066] This example demonstrates the preparation of carbon alewives froma 1 wt % single-wall carbon nanotube/oleum/water mixture.

[0067] The same experiments of Examples 4 and 5 were done except thatthe starting material was a 1 wt % single-wall carbonnanotube/oleum/water mixture. The alewives formed using the 1%single-wall carbon nanotube/oleum/water mixture were similar in size andshape to those formed from the 0.25 wt % single-wall carbonnanotube/oleum/water mixture.

Example 8

[0068] This example demonstrates that alewives are not formed in 98%H₂SO₄.

[0069] The same experiments of Examples 4 and 5 were done except thatthe starting material was a mixture of 1 wt % single-wall carbonnanotubes in 98% sulfuric acid. The product was collected in ether,washed and recovered as a bucky paper. A bucky paper is a thin mat ofentangled single-wall carbon nanotubes and single-wall carbon nanotuberopes. No alewives were observed. The ropes observed in this sample haduniform thicknesses from about 20 nm to about 30 nm. At lowermagnifications, the morphology resembled a continuous sheet of crumpledpaper.

Example 9

[0070] This example demonstrates the preparation of fibers of alignedsingle-wall carbon nanotubes extruded from a mixture of single-wallcarbon nanotubes and 100% sulfuric acid.

[0071] Single-wall carbon nanotubes (HiPco™ single-wall carbon nanotubesobtained from Carbon Nanotechnologies, Inc., Houston, Tex.) werepurified. A 6 wt % mixture of the purified single-wall carbon nanotubesin 100% sulfuric acid was prepared. The mixture was heated at 110° C.and mixed under an argon atmosphere for 72 hours. The argon pressure waskept slightly greater than atmospheric to provide a positive pressurewithin the vessel. A water-cooled condenser was used to prevent the lossof sulfur trioxide.

[0072] Under an inert argon atmosphere, approximately 5 mls of themixture was removed using a stainless steel syringe. While still underan inert argon atmosphere, the syringe was secured to a syringe pump,mounted vertically over a coagulation column. Fiber samples wereextruded through stainless steel dies of varying lengths in the range of1 inch and 4 inches and having orifices with diameters of 500 microns,250 microns and 125 microns. The extrusion was done into differentcoagulants without exposing the nanotube mixture to an air gap. Thecoagulants included diethyl ether, 10% H₂SO₄(aq), ethyleneglycol-diethyl ether and 10% H₂SO₄(aq) followed by diethyl ether. Fibersof at least 10 cm in length were extruded for subsequent testing andcharacterization. Tension was not applied during extrusion. The fiberswere removed from the coagulant bath and allowed to dry in air withoutany applied tension.

[0073] The fibers were analyzed by Raman spectroscopy to determine thedegree of internal alignment of the single-wall carbon nanotubes. Theratio of the Raman intensity of the E_(2g) mode at 1593 cm⁻¹ using alinearly polarized laser beam from a 780-nm diode laser was determinedfrom spectra taken for parallel and perpendicular orientations to theaxis of each fiber. Five data points for each orientation were recorded.A Chauvenet's Criterion of ½ was used for analyzing the “reasonableness”of data points. Table 1 lists the Polarized Raman Ratio, R, using themean parallel and perpendicular intensities and the standard deviationof the mean. The Fraser fraction, f, an indication of the nanotubealignment, was also calculated. See Table 1 below. TABLE 1 PolarizedOrifice Tube Raman Fraser Diameter Length Coagulant Ratio, R Fraction ƒ500 μm 1″ Diethyl Ether 15 ± 3.8 0.74 500 μm 2″ Diethyl Ether 9 ± 2 0.62 500 μm 3″ Diethyl Ether 11 ± 5.4 0.67 500 μm 4″ Diethyl Ether 11 ±4.6 0.67 250 μm 2″ Diethyl Ether 14 ± 2.3 0.72 125 μm 2″ Diethyl Ether22 ± 2.5 0.81 125 μm 4″ Diethyl Ether 21 ± 2.6 0.80 125 μm 2″ 10% H₂SO₄in Water  8 ± 1.7 0.58 125 μm 2″ Ethylene Glycol  5 ± 2.2 0.44 DiethylEther 125 μm 2″ 10% H₂SO₄ in Water, 14 ± 3.4 0.72 then Diethyl Ether

[0074] Four point resistivity measurements as a function of temperaturewere performed on the fibers extruded from 6 wt % single-wall carbonnanotube/100% H₂SO₄ through the 125 μm diameter, 2″ long die intodiethyl ether. The fiber sample was also annealed under vacuum at 1420°K for 2 hours and the resistivity measurements repeated. FIG. 6 showsthe resistivity data as a function of temperature for the raw andannealed fibers. Resistivity at 200° K for the annealed and raw fibersamples was 2.89 mΩ·cm and 0.30 mΩ·cm, respectively.

[0075] Thermopower measurements were performed on the same raw andannealed fibers extruded from a 6 wt % single-wall carbon nanotube/100%H₂SO₄ mixture through a 125 μm diameter, 2″ long die into diethyl ether.FIG. 7 shows thermopower as a function of temperature. Thermopower at200° K for the annealed and raw fiber samples was 41.05 μV/K and 12.02μV/K, respectively.

[0076] Differential thermopower as a function of temperature wasdetermined for the same raw and annealed fibers extruded from a 6 wt %single-wall carbon nanotube/100% H₂SO₄ mixture through a 125 μmdiameter, 2″ long die into diethyl ether. FIG. 8 shows differentialthermopower as a function of temperature. Differential thermopower at200° K for the annealed and raw fiber samples was 0.092 μV/K² and 0.038μV/K², respectively.

[0077] All of the compositions and methods disclosed and claimed hereincan be made and executed without undue experimentation in light of thepresent disclosure. While the compositions and methods of this inventionhave been described in terms of preferred embodiments, it will beapparent to those of skill in the art that variations may be applied tothe compositions and methods and in the steps or in the sequence ofsteps of the method described herein without departing from the concept,spirit and scope of the invention. More specifically, it will beapparent that certain agents which are both chemically andphysiologically related may be substituted for the agents describedherein while the same or similar results would be achieved. All suchsimilar substitutes and modifications apparent to those skilled in theart are deemed to be within the spirit, scope and concept of theinvention as defined by the appended claims.

What is claimed is:
 1. A method of making a fiber of aligned single-wallcarbon nanotubes, comprising: (a) mixing single-wall carbon nanotubeswith an anhydrous acid selected from the group consisting of 100%sulfuric acid and a superacid to form a single-wall carbon nanotube/acidmixture, and (b) spinning the single-wall carbon nanotube/acid mixtureto form a fiber.
 2. The method of claim 1, wherein the superacid isselected from the group consisting of a Brønsted superacid, a Lewissuperacid, a Brønsted-Lewis conjugate superacid and mixtures thereof. 3.The method of claim 1, wherein the Brønsted superacid is selected fromthe group consisting of superacids include perchloric acid,chlorosulfuric acid, fluorosulfuric acid, chlorosulfonic acid,fluorosulfonic acid, perfluoroalkanesulfonic acid,trifluoromethanesulfonic acid, higher perfluoroalkanesulfonic acid,C₂F₅SO₃H, C₄F₉SO₃H, C₅F₁₁SO₃H, C₆F₁₃SO₃H, C₈F₁₇SO₃H,

and α, ω-perfluoroalkanedisulfonic acid.
 4. The method of claim 1,wherein the Lewis superacid is selected from the group consisting ofantimony pentafluoride, arsenic pentafluoride, tantalum pentafluorideand niobium pentafluoride.
 5. The method of claim 1, wherein theBrønsted-Lewis conjugate superacid is selected from the group consistingof oleum, polyphosphoric acid-oleum mixtures, tetra(hydrogensulfato)boric acid-sulfuric acid, fluorosulfuric acid-antimonypentafluoride, fluorosulfuric acid-sulfur trioxide, fluorosulfuricacid-arsenic pentafluoride, HSO₃F:HF:SbF₅, HSO₃F:SbF₅:SO₃, aperfluoroalkanesulfonic acid-based system, C_(n)F_(2n+1)SO₃H:SbF₅, wheren=1, 2 or 4, CF₃SO₃H:B(SO₃CF₃)₃, hydrogen-fluoride-antimonypentafluoride, hydrogen fluoride-tantalum pentafluoride, hydrogenfluoride-boron trifluoride, a conjugate Friedel-Crafts acid, HBr:AlBr₃,and HCl:AlCl₃.
 6. The method of claim 1, wherein the superacid is oleum.7. The method of claim 1, wherein the oleum contains up to about 30%SO₃.
 8. The method of claim 1, wherein the superacid istrifluoromethanesulfonic acid.
 9. The method of claim 1, wherein thesingle-wall carbon nanotubes are at a concentration range between about0.01 wt % and about 10 wt % in the acid.
 10. The method of claim 1,wherein the single-wall carbon nanotubes are at a concentration rangebetween about 4 wt % and about 10 wt % in the acid.
 11. The method ofclaim 1, wherein the single-wall carbon nanotubes are at a concentrationrange between about 6 wt % and about 8 wt % in the acid.
 12. The methodof claim 1, wherein the mixing step is done in a time range betweenabout 3 hours and about 3 days.
 13. The method of claim 1, wherein thespinning step comprises wet spinning into a coagulant.
 14. The method ofclaim 13, wherein the coagulant is selected from the group consisting ofwater, diethyl ether, 10% sulfuric acid, ethylene glycol and mixturesthereof.
 15. The method of claim 1, wherein the aligned single-wallcarbon nanotubes in the fiber have a Fraser fraction of at least about0.25.
 16. The method of claim 1, wherein the aligned single-wall carbonnanotubes in the fiber have a Fraser fraction of at least about 0.5. 17.The method of claim 1, wherein the aligned single-wall carbon nanotubesin the fiber have a Fraser fraction of at least about 0.7.
 18. Themethod of claim 1, further comprising washing the fiber.
 19. The methodof claim 18, wherein the washing is done in a liquid selected from thegroup consisting of water, diethyl ether, methanol and combinationsthereof.
 20. The method of claim 1, further comprising drying the fiber.21. The method of claim 20, wherein the drying is done by a methodselected from the group consisting of heating, air drying, vacuum dryingand a combination thereof.
 22. The method of claim 1, further comprisingannealing the fiber.
 23. The method of claim 22, wherein the annealingis done at a temperature in the range between about 400° C. and about800° C.
 24. The method of claim 1 further comprising subjecting thefiber to a reducing environment at an elevated temperature.
 25. Themethod of claim 24, wherein the temperature is up to about 450° C. 26.The method of claim 1, wherein the mixing step is done under an inertatmosphere.
 27. The method of claim 1, wherein the mixing step is doneat a temperature range between about room temperature and about 150° C.28. A fiber of aligned single-wall carbon nanotubes made by the processcomprising: (a) mixing single-wall carbon nanotubes with an anhydrousacid selected from the group consisting of 100% sulfuric acid and asuperacid to form a single-wall carbon nanotube/acid mixture, and (b)spinning the single-wall carbon nanotube/acid mixture to form a fiber.29. The fiber of claim 28, wherein the superacid is selected from thegroup consisting of a Brønsted superacid, a Lewis superacid, aBrønsted-Lewis conjugate superacid and mixtures thereof.
 30. The fiberof claim 28, wherein the Brønsted superacid is selected from the groupconsisting of superacids include perchloric acid, chlorosulfuric acid,fluorosulfuric acid, chlorosulfonic acid, fluorosulfonic acid,perfluoroalkanesulfonic acid, trifluoromethanesulfonic acid, higherperfluoroalkanesulfonic acid, C₂F₅SO₃H, C₄F₉SO₃H, C₅F₁₁SO₃H, C₆F₁₃SO₃H,C₈F₁₇SO₃H,

and α, ω-perfluoroalkanedisulfonic acid.
 31. The fiber of claim 28,wherein the Lewis superacid is selected from the group consisting ofantimony pentafluoride, arsenic pentafluoride, tantalum pentafluorideand niobium pentafluoride.
 32. The fiber of claim 28, wherein theBrønsted-Lewis conjugate superacid is selected from the group consistingof oleum, polyphosphoric acid-oleum mixtures, tetra(hydrogensulfato)boric acid-sulfuric acid, fluorosulfuric acid-antimonypentafluoride, fluorosulfuric acid-sulfur trioxide, fluorosulfuricacid-arsenic pentafluoride, HSO₃F:HF:SbF₅, HSO₃F:SbF₅:SO₃, aperfluoroalkanesulfonic acid-based system, C_(n)F_(2n+1)SO₃H:SbF₅, wheren=1, 2 or 4, CF₃SO₃H:B(SO₃CF₃)₃, hydrogen-fluoride-antimonypentafluoride, hydrogen fluoride-tantalum pentafluoride, hydrogenfluoride-boron trifluoride, a conjugate Friedel-Crafts acid, HBr:AlBr₃,and HCl:AlCl₃.
 33. A fiber of aligned single-wall carbon nanotubes,wherein the aligned single-wall carbon nanotubes in the fiber have aFraser fraction of at least about 0.25.
 34. The fiber of claim 33,wherein the aligned single-wall carbon nanotubes in the fiber have aFraser fraction of at least about 0.5.
 35. The fiber of claim 33,wherein the aligned single-wall carbon nanotubes in the fiber have aFraser fraction of at least about 0.7.
 36. The fiber of claim 33,wherein the fiber is present in an article selected from the groupconsisting of fibers, cables, and electrical transmission lines.
 37. Thefiber of claim 33, wherein the fiber is present in an article selectedfrom the group consisting of electrochemical electrodes, batteryelectrodes, sensors, and transducer elements.
 38. The fiber of claim 33,wherein the fiber is present in an article selected from the groupconsisting of airframes, components for aircraft, components formissiles, vehicle bodies, bullet-proof vests, armor, and ship hulls. 39.The fiber of claim 33, wherein the fiber is present in a catalystsupport.
 40. The fiber of claim 33, wherein the fiber is present in anarticle selected from the group consisting of chemically inertmaterials, biologically-inert materials, materials that absorb moietiesthat intercalate, materials that support moieties that intercalate andmaterials that dispense moieties that intercalate.
 41. The fiber ofclaim 33 wherein the fiber is present in an article selected from thegroup consisting of skis, surfboards, sails, racquets and other sportinggoods.
 42. The fiber of claim 33 wherein the fiber is present in wovenmaterial wherein the woven material is woven with other fibers selectedfrom the group consisting of single-wall carbon nanotube fibers, naturalfibers, synthetic fibers and combinations thereof.
 43. The fiber ofclaim 33, wherein the fiber is present in an article selected from thegroup consisting of structural materials, impact-resistant materials,structural laminates having layers with different tube orientations,pressure vessel exteriors, and pressure vessel reinforcement, thermalmanagement materials, and heat-resistant materials.
 44. The fiber ofclaim 43, wherein the thermal management material is a heat-transportingmaterial.
 45. A method for forming intercalated single-wall carbonnanotubes, comprising: mixing single-wall carbon nanotubes with ananhydrous acid selected from the group consisting of 100% sulfuric acid,an intercalating species and a superacid, under an inert atmosphere at atemperature ranging from about room temperature to about 150° C. for atime sufficient to form a single-wall carbon nanotube/acid mixture. 46.The method of claim 45, wherein the superacid is selected from the groupconsisting of a Brønsted superacid, a Lewis superacid, a Brønsted-Lewisconjugate superacid and mixtures thereof.
 47. The method of claim 46,wherein the Brønsted superacid is selected from the group consisting ofsuperacids include perchloric acid, chlorosulfuric acid, fluorosulfuricacid, chlorosulfonic acid, fluorosulfonic acid, perfluoroalkanesulfonicacid, trifluoromethanesulfonic acid, higher perfluoroalkanesulfonicacid, C₂F₅SO₃H, C₄F₉SO₃H, C₅F₁₁SO₃H, C₆F₁₃SO₃H, C₈F₁₇SO₃H,

and α, ω-perfluoroalkanedisulfonic acid.
 48. The method of claim 46,wherein the Lewis superacid is selected from the group consisting ofantimony pentafluoride, arsenic pentafluoride, tantalum pentafluorideand niobium pentafluoride.
 49. The method of claim 46, wherein theBrønsted-Lewis conjugate superacid is selected from the group consistingof oleum, polyphosphoric acid-oleum mixtures, tetra(hydrogensulfato)boric acid-sulfuric acid, fluorosulfuric acid-antimonypentafluoride, fluorosulfuric acid-sulfur trioxide, fluorosulfuricacid-arsenic pentafluoride, HSO₃F:HF:SbF₅, HSO₃F:SbF₅:SO₃, aperfluoroalkanesulfonic acid-based system, C_(n)F_(2n+1)SO₃H:SbF₅, wheren=1, 2 or 4, CF₃SO₃H:B(SO₃CF₃)₃, hydrogen-fluoride-antimonypentafluoride, hydrogen fluoride-tantalum pentafluoride, hydrogenfluoride-boron trifluoride, a conjugate Friedel-Crafts acid, HBr:AlBr₃,and HCl:AlCl₃.
 50. The method of claim 45, wherein the intercalatingspecies comprises a chemical selected from the group consisting ofconcentrated nitric acid, concentrated sulfuric acid, 100% sulfuricacid, oleum, mixtures of polyphosphoric acid and oleum, fluorosulfuricacid, chlorosulfuric acid, sulfonic acid, fluorosulfonic acid,chlorosulfonic acid, alkyl sulfonic acid, aromatic sulfonic acid,perchloroalkyl sulfonic acid, perchloroaromatic sulfonic acid,perfluoroalkyl sulfonic acid, perfluoroaromatic sulfonic acid, metalhalide, hydrogen fluoride, chlorine, fluorine, bromine, iodine andmixtures thereof.
 51. The method of claim 45, wherein the single-wallcarbon nanotubes are at a concentration range between about 0.01 wt %and about 10 wt % in the acid.
 52. The method of claim 45, wherein theanhydrous acid is an aggregate substantially redispersing acid.
 53. Themethod of claim 45, wherein the intercalated single-wall carbonnanotubes form super ropes.
 54. The method of claim 45, wherein theanhydrous acid is an aggregate redispersible acid.
 55. The method ofclaim 45, wherein the intercalated single-wall carbon nanotubes formsuper ropes.
 56. The method of claim 55, wherein the super ropes have adiameter in the range between about one-half micron and about 2 microns.57. The method for dispersing single-wall carbon nanotubes comprising:(a) providing intercalated single-wall carbon nanotubes, and (b) mixingthe intercalated nanotubes in a fluid material selected from the groupconsisting of water, surfactant, dimethyl formamide, chloroform,dichlorobenzene, molten polymer, molten ceramic and mixtures thereof.58. A composition of aligned single-wall carbon nanotubes produced bythe process comprising: (a) mixing single-wall carbon nanotubes with ananhydrous acid selected from the group consisting of 100% sulfuric acidand a superacid to form a single-wall carbon nanotube/acid mixture; and(b) incorporating water into the single-wall nanotube/acid mixture toform a composite comprising the aligned single-wall carbon nanotubes,wherein the aligned single-wall carbon nanotubes within the compositeare substantially redispersible.
 59. The composition of claim 58,wherein the aligned single-wall carbon nanotubes within the compositeare redispersible.